Closure ring assembly for steel drums

ABSTRACT

Interlocking end lugs are provided in an improved closure split ring assembly for steel drums. The interlocking end lugs facilitate the tangential alignment of the ring to seal the lid on the drum and lock it in place.

RELATED APPLICATION

This application is a continuation-in-part application of U.S. patent application Ser. No. 11/421,498, filed Jun. 1, 2006, entitled “Closure Ring Assembly for Steel Drums”, which, in turn, is a continuation-in-part application of U.S. patent application Ser. No. 11/130,299, filed May 16, 2005, entitled “Closure Ring Assembly for Steel Drums” and the entire disclosures of each of these applications are incorporated herein by reference.

FIELD OF THE INVENTION

This invention is directed to closure assemblies for steel drums that are used for transporting non-bulk materials. In particular, this invention is directed to an improved closure ring assembly capable of ensuring that the drum remains secure and leakproof during transit.

BACKGROUND OF THE INVENTION

Conventional closure ring assemblies for drums include a split closure ring having adjacent ends with lugs on each end. One of the lugs has an unthreaded hole and the other lug has a threaded hole for receiving a conventional bolt. When the lid of the drum is secured to its opening, the closure ring is placed around the lid and the bolt is inserted through the unthreaded hole of one of the lugs to engage the threaded hole of the other lug. As the threaded bolt engages the threaded hole, the ends of the closure ring are drawn together to tighten the closure ring around the lid and the drum.

Organizations have developed packaging standards that require compliance with certain vibration, drop and hydrostatic tests to ensure that the drums remain secure and leakproof during transit. Typically, because of the excessive radial clearance between the tie bolt and the enlarged opening of the unthreaded lug, the ends of the closed split ring are prone to separation and movement under impact. This causes ring distortion and seal failure eventually leading to leakage, container failure and possible contamination of both the storage container and its surroundings.

A number of closure ring assemblies have been proposed to overcome the common problems associated with their designs. For instance, in the case of U.S. Pat. No. 5,584,410, a threaded jam nut is mounted on the bolt between the two lugs to prevent unwanted radial movement between the unthreaded lug and the bolt when the split ring is closed. The jam nut is included in the assembly to secure the unthreaded lug between the bolt head and the jam nut to aid in withstanding impact forces. Other designs have been provided to achieve a seal for the open-headed drum that prevents against leakage of the contents, such as those disclosed in U.S. Pats. Nos. 3,907,349; 5,193,864; 5,215,206 and 6,435,576. In the case of the '864 patent, the common problem of undesired movement of the bolt in the unthreaded hole of the lug which can disrupt the sealed relationship between the lid and the drum is addressed by employing a bolt head which is tapered to cooperate with the tapered, unthreaded lug. When the bolt head is drawn into engagement with the unthreaded lug, it causes a guided wedging action and a tangential alignment movement between the lugs and ring ends, with locking nuts adjusted to set the bolt for the desired tension of the locking ring. In the case of the '576 patent, the problem of undesired radial and axial movement of the closure ring is addressed by designing a bolt with a slip sleeve which is flush with the periphery of a large unthreaded hole. The sleeve thereby reduces the movement that is allowable within the large threaded hole to secure the connection of the bolt to the lugs and reinforce the closure ring connection to the drum.

While the designs of existing patents have sought to address and overcome the common problem discussed above, there still remain difficulties with the conventional closure ring assemblies in achieving a tight connection between the closure ring and the drum, thereby complying with vibration, drop and hydrostatic test standards.

Notwithstanding the efforts to achieve tighter connections between the closure ring and the drum with the prior designs described above, a continuing need exists to provide a more secure connection.

SUMMARY OF THE INVENTION

This invention is directed to an improved closure ring assembly for steel drums which includes interlocking end lugs for the split ring. The interlocking end lugs facilitate the tangential alignment of the ring to seal the lid on the drum and lock it in place.

The improved closure ring assembly for securing a lid to a cylindrical drum comprises an annular closure split ring having first and second end lugs. The first end lug has an unthreaded hole and the second threaded lug has a threaded hole. A tie bolt having a head and a threaded cylindrical end is adapted for insertion through the first unthreaded lug to threadingly engage the second threaded lug and draw the lugs together. The first and second lugs each have an end face for interlocking the lugs and tangentially aligning the annular closure ring to close the ring for sealing the lid on the drum.

In a preferred form of the invention, the first end lug face has a conical shoulder integrally formed therein and the second threaded lug is tapered to receive the conical shoulder such that, when the tie bolt threadingly draws the lugs into successive engagement, there is provided a guided wedging action between the lugs and tangential alignment of the ring ends to seal the drum.

In another form of the invention, each of the end faces of the first and second lugs may be modified for interlocking the lugs and tangentially aligning the annular closure ring for sealing the lid on the drum. In this form of the invention, the end faces are flat or plane for engagement of one another such that, when the tie bolt threadingly draws the lugs into successive engagement, the end faces abut one another thereby interlocking the lugs together and tangentially aligning the annular closure ring to close the ring for sealing the lid on the drum. The tie bolt which is used to threadingly draw the lugs into successive engagement may be in the form described above with a tapered shoulder for cooperating with the tapered face of the first unthreaded lug. In another form, the tie bolt has a cylindrical shoulder which cooperates with the hole of the first unthreaded lug such that it is flush with the hole and assists in facilitating the successive engagement of the lugs to provide the tangential alignment of the ring ends to seal the drum. Other alternative embodiments of the lug faces can be arranged. For instance, outwardly projecting teeth of the end faces can be provided to further facilitate locking engagement of the lugs. Similarly, both sides of the lugs can have outwardly projecting teeth such that the head of the tie bolt or nut can engage the projecting teeth of the adjacent lug to frictionally engage the lug and assist in locking the end lugs together.

In its most preferred form, the bolt head has a tapered shoulder for cooperating with a tapered face of the first unthreaded lug such that, when the tie bolt draws the lugs into engagement, the tapered bolt head and cooperating unthreaded lug facilitate the successive engagement of the lugs to provide the guided wedging action between the lugs and tangential alignment of the ring ends to seal the drum.

In another preferred form of the invention, the tie bolt has a threaded cylindrical end which is provided with a resilient solid plastic coating fused onto its surface along a plurality of threads for sealing and locking the tie bolt in engagement with the second threaded lug. The tie bolt has a prevailing torque locking feature which is provided by the fused plastic on its surface. The plastic is normally an engineering plastic, such as nylon (polyamide polymer), that is used in the form of a patch which covers a segment of the threads, about 4-6, spaced apart from the end of the tie bolt threaded cylindrical end. Other engineering plastics include polyesters, PVC, polyurethane, polycarbonate, polyarylate, polyphenylene ether, polyethersulfone, polyarylsulfone; polyphenylene sulfide, polyether ketone, and polyether ether ketone. The plastic coating can be in the form of a partial covering of a segment of the threads, or, it may completely surround the circumference of the threaded cylinder. The patch or coated segment of the threads is spaced apart from the end of the tie bolt cylindrical end to facilitate the ease of starting the tie bolt into the threaded end lug. The use of the tie bolt with the prevailing torque locking feature of the fused plastic coating, in conjunction with the abutting end interlocking lugs, further assures the integrity of the applied torque during the closing of the ring assembly. The coated tie bolt also provides excellent locking performance as well as increased sealing ability attributable to the resilient plastic filling the threads between the bolt and the threaded lug. The coated tie bolt also provides vibration dampening characteristics to the ring assembly and meets the test procedures for the performance of Nonmetallic Resistant Element Prevailing Torque Fasteners IFI-124 of the Industrial Fasteners Institute. The interlocking abutting lugs design of this invention coupled with the coated tie bolt eliminates the jam nut, which has been used in prior art designs, thereby saving both time and labor for fillers and emptiers of containers. The inventive design also is safer by eliminating the pinch point on assembling jam nuts needed between lugs in prior art designs. Furthermore, the coated tie bolts can be opened and reclosed multiple times with similar performance characteristics.

In contrast to the prior designs, the closure ring assembly of the present invention provides for closure ring lugs which interlock and align the ring ends resulting in a tighter connection between the closure ring ends and the drum. Moreover, the closure ring assembly of the present invention satisfies the need for a reliable closure ring assembly which meets hydrostatic and drop test requirements.

Accordingly, the present invention satisfies a need to provide an improved closure ring assembly for a cylindrical steel drum that will meet current industry standards. The invention also meets another objective of providing an improved closure ring assembly for drums that overcomes the problem of undesired radial and axial movement of the closure ring.

These and other objectives and advantages of the present invention will become more apparent from the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

An annular closure ring assembly embodying the principles of the present invention is shown in the accompanying drawings wherein:

FIG. 1 is a partial exploded perspective view of the drum, drum cover and closure assembly embodying the present invention.

FIG. 2 is a top plan view of the closure assembly shown in FIG. 1 which illustrates the condition of the parts when the closure assembly is in closed condition.

FIG. 3 is a cross sectional view taken substantially along the line 3-3 of FIG. 2 looking in the direction of the arrows.

FIG. 4 is a cross sectional view of another embodiment of the invention with the end faces of the lugs modified to provide flat or plane surfaces for interlocking the lugs and tangentially aligning the annular closure ring. In this embodiment, a different tie bolt is shown having a cylindrical shoulder for cooperating with the hole of the first unthreaded lug.

FIG. 5 is a partial perspective view of an end lug illustrating the outwardly projecting teeth bordering the lug opening for locking engagement of the underside of the tie bolt thereby enhancing interlocking of the lugs.

FIG. 6 is a side view of another form of a tie bolt suitable for use in this invention which has a resilient solid plastic coating fused onto its surface along a plurality of threads.

FIG. 6A is a cross-sectional view of the tie bolt taken along lines 6A-6A of FIG. 6.

FIG. 6B is a cross-sectional view of an alternative embodiment of the coated tie bolt from FIG. 6.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference to FIGS. 1-3 of the drawings, the drum ring of this invention is split to provide two adjacent ends 11, 12 that are capable of surrounding an open-headed drum 13 and secure the lid 14. At the ring ends are lugs 15, 16, each having a hole passing tranversely therethrough to receive a tie bolt 20. One of the lugs 15 is threaded to receive the threaded end 21 of the tie bolt 20 and the other lug 16 has an unthreaded hole 22 which is large enough for the tie bolt 20 to pass through it. A tapered conical shoulder 23 is integrally formed onto the bolt 20 head which is designed to be substantially flush with the tapered face 24 of lug 16. The unthreaded lug 16 has a conical shoulder 26 integrally formed on its opposite face 27 which is designed to be flush with a taper in the face 28 of the second threaded lug 15. Accordingly, when the unthreaded lug 16 is drawn into engagement with the threaded lug 15 by turning the bolt 20 head, the bolt head shoulder 23 engages the tapered face 24 of the unthreaded lug 16 to provide a guided wedging action between conical shoulder 26 and the tapered face 28 of the threaded lug 15. As a result, the ring ends 11, 12 are brought into tangential alignment and, as the bolt 20 is rotated to drive the lugs 15, 16 toward one another, the lugs are brought into frictional and locking engagement to close the ring for sealing the drum lid.

In the most preferred form, the tie bolt 20 head is multi-faceted to facilitate turning the tie bolt down with a wrench and the tie bolt also has a conical surface 23 which engages the conical face 24 of the unthreaded lug end 16. In this most preferred form, the opposite face of the unthreaded lug 16 also has a conical shoulder 26 which fits into the recessed conical face 28 of the second threaded lug 15. With this most preferred arrangement, when the tie bolt 20 is rotated to draw the lugs 15, 16 toward one another, the lugs are brought into frictional and locking engagement to tangentially close the ring for sealing the drum. In contrast to the prior art as represented by the above patents in the background, which are focused on the various features of the lug and bolt arrangements such as headed bolts, sleeves, locking nuts, etc., there has been no disclosure or suggestion in the prior art of an interlocking lug arrangement as provided by this invention. Furthermore, there has been no disclosure or suggestion of the preferred embodiments of this invention which facilitate the sealing of an open-headed drum.

With reference to FIGS. 4 and 5, In another form of the invention, each of the end faces of the first and second lugs 41,42 may be modified for interlocking the lugs and tangentially aligning the annular closure ring for sealing the lid on the drum. In this form of the invention, the end faces 47,48 are flat or plane for engagement of one another such that, when the tie bolt 40 threadingly draws the lugs 41,42 into successive engagement, the end faces 47,48 abut one another thereby interlocking the lugs together and tangentially aligning the annular closure ring to close the ring for sealing the lid on the drum. The tie bolt 40 which is used to threadingly draw the lugs 41,42 into successive engagement may be modified to have a cylindrical shoulder 43 which cooperates with the hole 44 of the first unthreaded lug 41 such that it is flush with the hole and assists in facilitating the successive engagement of the lugs 41,42 to provide the tangential alignment of the ring ends to seal the drum. Other alternative embodiments of the lug faces can be arranged. For instance, with reference to FIG. 5, outwardly projecting teeth 51 of the end face of a lug further facilitate locking engagement of the lugs. Similarly, both sides of the lugs can have outwardly projecting teeth 51 such that the head of the tie bolt engages the projecting teeth 51 to frictionally engage the lug and assist in locking the end lugs together.

With reference to FIG. 6, another form of the tie bolt is illustrated. In this form, the tie bolt 60 has an engineering plastic coating 61 fused on its surface along the plurality of the threads of the bolt for sealing and locking the bolt in engagement with the second threaded end lug. FIGS. 6A and 6B, respectively, show both circumferential and partial coverage of the coating 61. There is a slight thickness to the coating 61, which is exaggerated slightly in FIGS. 6A and 6B for clarity.

The tie bolt 60 has a prevailing torque locking feature which is provided by the fused plastic 61 on its surface. The plastic is normally an engineering plastic that is used in the form of a patch which partially covers a segment, as shown in FIG. 6B, of the threads, about 4-6, spaced apart from the end of the tie bolt threaded cylindrical end. The plastic coating 61 can completely surround the circumference or periphery of the threaded cylinder, as shown in FIG. 6A. The patch or coated segment of the threads is spaced apart from the end of the cylindrical threaded end to facilitate the ease of starting the tie bolt into the threaded end lug.

The use of the tie bolt with the prevailing torque locking feature of the fused plastic coating, in conjunction with the abutting and interlocking lugs, further assures the integrity of the applied torque during the closing of the ring assembly. The coated tie bolt also provides excellent locking performance as well as increased sealing ability attributable to the resilient plastic filling the threads between the bolt and the threaded lug. The coated tie bolt also provides vibration dampening characteristics to the ring assembly and meets the test procedures, such as IFI-124 of the Industrial Fasteners Institute, along with other benefits as described above.

Other forms of this invention will become apparent in view of the description and preferred embodiments which are not intended to limit its scope. 

1. A closure ring assembly for securing a lid to a cylindrical drum comprising an annular closure split ring having a first unitary end lug and a second unitary end lug, said first end lug having an unthreaded hole and said second end lug having a threaded hole, a tie bolt having a head and a threaded cylindrical end for insertion through said first unthreaded lug to engage said second threaded lug for drawing the lugs together, said first and second lugs each having an end face directly abutting one another for interlocking said lugs together by frictionally abutting said end faces into locking engagement and tangentially aligning the annular closure ring to close the ring for sealing the lid on the drum.
 2. The assembly of claim 1 wherein said first lug end face has a conical shoulder integrally formed therein and the second threaded lug end face is tapered to receive the conical shoulder such that when the tie bolt draws the lugs together by frictionally abutting said end faces into locking engagement there is provided a guided wedging action and tangential alignment of the ring ends to seal the drum.
 3. The assembly of claim 1 wherein the bolt head has a tapered shoulder for cooperating with a tapered face of the first unthreaded lug opposite its end face such that when the tie bolt draws the lugs together by frictionally abutting said end faces into locking engagement, the tapered bolt head and cooperating unthreaded lug facilitate the engagement of the lugs to provide a guided wedging action and tangential alignment of the ring ends to seal the drum.
 4. The assembly of claim 3 wherein said bolt head shoulder is conically shaped.
 5. The assembly of claim 3 wherein the tapered face of the first unthreaded lug is conically shaped.
 6. The assembly of claim 1 wherein said first lug end face is plane and the second threaded lug end face is plane such that when the tie bolt draws the lugs together by frictionally abutting said end faces into locking engagement there is provided a locking action and tangential alignment of the ring ends to seal the drum.
 7. The assembly of claim 1 wherein the bolt head has a cylindrical shoulder for cooperating with the unthreaded hole of the first end lug to facilitate the engagement of the lugs for interlocking and tangential alignment of the ring ends to seal the drum.
 8. The assembly of claim 1 wherein the face of the first unthreaded lug has projecting teeth for cooperating with the bolt head to assist in interlocking the end lugs.
 9. The assembly of claim 1 wherein an end face of the first or second lug has projecting teeth to assist in interlocking the end lugs.
 10. A closure ring assembly for securing a lid to a cylindrical drum comprising an annular closure split ring having a first unitary end lug and a second unitary end lug, said first end lug having a tapered face with an unthreaded hole and said second lug having a threaded hole, a tie bolt having a head and a threaded cylindrical end for insertion through said first unthreaded lug to engage said second threaded lug for drawing the lugs together, wherein the bolt head has a tapered shoulder for cooperating with the tapered face of the first unthreaded lug, said first and second lugs each having an end face directly abutting one another for interlocking said lugs together by frictionally abutting said end faces into locking engagement, wherein said first lug end face has a conical shoulder integrally formed therein opposite its tapered face and the second threaded lug end face is tapered to receive the conical shoulder such that when the tie bolt draws the lugs into engagement there is provided a guided wedging action and tangential alignment of the ring ends to seal the drum.
 11. A closure ring assembly for securing a lid to a cylindrical drum comprising an annular closure split ring having a first unitary end lug and a second unitary end lug, said first end lug having an unthreaded hole and said second end lug having a threaded hole, a tie bolt having a head and a threaded cylindrical end for insertion through said first unthreaded lug to engage said second threaded lug for drawing the lugs together, wherein the bolt head has a cylindrical shoulder for cooperating with the hole of the first unthreaded lug, said first and second lugs each having a plane end face directly abutting one another for interlocking said lugs together by frictionally abutting said end faces into locking engagement such that when the tie bolt draws the lugs into engagement there is provided a locking action and tangential alignment of the ring ends to seal the drum.
 12. The assembly of claim 11 wherein the face of the first unthreaded lug has projecting teeth for cooperating with the bolt head to assist in interlocking the end lugs.
 13. The assembly of claim 11 wherein an end face of the first or second lug has projecting teeth to assist in interlocking the end lugs.
 14. The assembly of claim 1, 10, or 11 wherein the threaded cylindrical end of the bolt has a resilient solid plastic coating fused onto its surface along a plurality of threads for sealing and locking the bolt in engagement said second threaded lug.
 15. The assembly of claim 14 wherein the coating covers a segment of the threaded cylindrical end which is spaced apart from the threaded end of the bolt thereby facilitating the ease of starting the bolt in the threaded end lug.
 16. The assembly of claim 14 wherein the coating extends completely around the threaded cylindrical end of the bolt.
 17. The assembly of claim 14 wherein the coating extends partially around the circumference of the threaded cylindrical end of the bolt. 